Waste processing system door assembly

ABSTRACT

A door assembly for an air lock of a waste processing system comprising a vertical sliding door member having a perimeter entirely supported when the sliding door member is in a closed position and is sealed by a selectively inflatable gasket assembly located along the perimeter. The sliding door member is supported by inner and outer panels separated by a rectangular spacer gasket, wherein the inner and outer panels each contain a rectangular opening having a perimeter for receiving the inflatable gasket assembly. The inflatable gasket assembly includes a retainer frame and a rectangular inflatable seal element. The door assembly is opened and closed by including a pair of vertical tracks located between the inner and outer panels for receiving vertically extending ribs from the sliding door member. A longitudinal rack located on the sliding door member engages a pinion mounted on a shaft extending through an opening in the outer panel and a hydraulic motor is mounted on the outer panel for driving the pinion.

RELATED APPLICATION INFORMATION

This application is a continuation of U.S. application Ser. No.07/831,175 filed Feb. 5, 1992 U.S. Pat. No. 5,217,173.

BACKGROUND OF THE INVENTION

The present invention relates to waste processing systems for handlinghazardous or radioactive waste which must be totally enclosed and inwhich material is dumped and shredded before being conveyed for furthertreatment or incineration and, more particularly, to a door assembly forproviding a sealed environment in an air lock of the waste processingsystem.

Environmental laws require that hazardous material, includingradioactive material, either be incinerated, stabilized or processedunder certain prescribed conditions, or collected, packaged and storedat special sites. In any case, it is desirable to reduce the particlesize of the material as much as possible. In the case of material to beincinerated, small particle size insures more complete combustion andfacilitates feeding into an incinerator. In the case of material to bepackaged, reduction of particle size allows a greater amount of materialto be shipped within a given container. In the case of materials to bestabilized, small particle size insures more complete stabilization. Inthe case of material to be processed in a slagging mode incinerator,small particle size insures more complete breakdown of materials.

Since the handling of such material may give rise to toxic orradioactive fumes, or create the hazard of an explosion, it is desirableto process such material in enclosed environments. For example, inRobertson U.S. Pat. No. 5,022,328, there is disclosed a system in whichcontainerized waste is conveyed upwardly through an elevator, thenhorizontally to an air lock where the containerized waste is dumpedthrough a drop chute into a shredder device which grinds the wastematerial and containers, then is injected by a feed screw into anincinerator. A disadvantage with this system is that the material iselevated and conveyed horizontally in a system which is not enclosed orprotected from the environment. Further, the system disclosed in theRobertson patent is not capable of receiving and dumping hazardous orradioactive material from reusable containers. Accordingly, there is aneed for a waste processing system in which material can be received atground level or intermediate levels, then processed for storage,stabilization, incineration or additional processing in a totallyenclosed environment at a different level. Further, such a system shouldbe able to handle reusable containers.

SUMMARY OF THE INVENTION

The present invention is a door assembly for a waste processing systemwherein the system is adapted to handle hazardous and radioactivecontainerized material in which the material is received substantiallyat ground level or intermediate levels, is elevated, dumped, thematerial is shredded, blended, mixed, homogenized or combined withstabilizing agents, and is injected into an incinerator or a containeror into an additional processing stage. The entire system is enclosedand maintained in a low oxygen or inert gas environment. Gas pressurewithin the system can be maintained positive (greater than atmospheric)or negative (less than atmospheric) as the application requires. As aresult, the likelihood of contamination reaching the ambient during theelevating, dumping, shredding and injecting processes is substantiallyreduced, as is the likelihood of explosion.

The system includes one or more powered infeed conveyors, each havingits own air lock. Each air lock has an inner and an outer door assemblywhich include a sliding door member that is supported entirely about itsperiphery when closed and is sealable. These door seal assemblies can beof conventional mechanically-loaded lip or inflatable design. Seals canbe located on one side of the door or on both sides, providing redundantprotection. Accordingly, the doors are better able to withstandexplosions than prior art air lock doors, and yet are of a relativelysimple construction.

The door assembly further includes plate-like inner and outer panelsseparated by a rectangular spacer gasket for supporting the sliding doormember. The inner and outer panels and the spacer gasket are positionedand held together by a ring of bolt and nut assemblies. The inner andouter panels each contain a rectangular opening having a perimeter forreceiving the inflatable gasket assembly. The inflatable gasket assemblycomprises a retainer frame and a rectangular inflatable seal element.

Movement of the door is accomplished by the inner and outer panelscontaining a pair of vertical tracks for receiving vertically extendingribs located on the sliding door member. The sliding door member furtherincludes a longitudinal rack which engages a pinion mounted on a shaftextending through an opening in the outer panel. The pinion is driven bya hydraulic motor mounted on the outer panel.

The air locks of the system are connected to a totally enclosed,substantially vertical elevator having a powered conveyor on theelevator platform for receiving containerized waste from one or more airlocks. The elevator platform elevates the containerized waste to a dualpurpose discharger. The discharger includes primary and auxiliary rammembers. If the waste is in disposable containers, the primary rammember transports the containers horizontally from the elevator to bedropped into the shredder. If the waste is in reusable containers, theram member grips the container, transports the container to a positionabove the shredder, inverts the container to dump the contents, uprightsthe container and retracts it to the elevator for return to the airlocks empty.

Accordingly, it is an object of the present invention to provide doorassemblies for a waste processing system in which waste material isreceived at ground level or intermediate levels, is elevated, dumped,shredded, blended and fed to an incinerator, container or additionalprocessor, all in an enclosed environment in which the atmosphere may bemaintained in a low oxygen or inert gas environment; a door assembly fora waste processing system in which the inlet air locks include slidingdoors which are supported about their entire peripheries when closed andare sealable; and a door assembly for a waste processing system which isrelatively safe to operate and relatively easy to maintain.

Other objects and advantages of the present invention will be apparentfrom the following description, the accompanying drawings and theappended claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a somewhat schematic, perspective view of a waste processingsystem incorporating the present invention;

FIG. 2 is a detail of the system of FIG. 1 showing an infeed conveyorand air lock, in which the side panels of the air lock have beenremoved;

FIG. 3 is a detail of the system of FIG. 1 showing an air lock door;

FIG. 4 is an exploded, perspective view of the door assembly of FIG. 3;

FIG. 5 is a section taken at Line 5--5 of FIG. 3 in which the centersection has been broken away;

FIG. 6 is a detail showing the elevator and discharger structure inwhich the side panels have been removed to show the interior of thesecomponents;

FIG. 7 is a detail of the discharger of FIG. 6 showing the ram members;

FIG. 8 is an exploded, perspective view of the ram members of FIG. 7 anda canister;

FIG. 9 is a detail showing the discharger of FIG. 6 in which a reusablecanister is positioned on the elevator platform;

FIG. 10 is the detail of FIG. 9 in which the opposing ram member isengaging the canister;

FIG. 11 is the detail of FIG. 9 in which the canister has beentransported to the drop chute area;

FIG. 12 is the detail of FIG. 11 in which the canister has been invertedto dump its contents;

FIG. 13 is a detail of the discharger of the system of FIG. 1 in whichdisposable containers are supported on the elevator platform;

FIG. 14 is a detail of the system of FIG. 1 showing a schematic sideelevation of the shredder and injector components;

FIG. 15 is a detail showing a perspective view of the slide box of thesystem of FIG. 1;

FIG. 16 is a section taken at Line 16--16 of FIG. 15;

FIG. 17 is a section taken at Line 17--17 of FIG. 15;

FIG. 18 is a schematic showing the controller component of the system ofFIG. 1;

FIG. 19 is a schematic showing the controller of FIG. 17 and theconnections for operating the ram carriages;

FIG. 20 is a schematic, perspective view of the waste processing systemutilized with a rotary kiln having an elevated infeed shoot;

FIG. 21 is a perspective view of the waste processing system feeding asag mill having an elevated inlet;

FIG. 22 is a schematic, perspective view of the waste processing systemin which a rotary kiln fed by the system is at a different elevationthan the infeed and outfeed conveyors; and

FIG. 23 is a perspective view of the waste processing system in which asecond infeed conveyor is utilized.

DETAILED DESCRIPTION

As shown in FIG. 1, the waste processing system of the present inventionincludes an infeed conveyor 20, an outfeed conveyor 22, elevator 24,discharger 26, hopper extension 28, dual auger assembly 30, single augerassembly 32, injector 34, and slide box 36. The aforementionedcomponents all are totally enclosed so that waste material beingreceived on infeed conveyor 20 enters a controlled atmosphereenvironment for the entire process, until the material either enters anincinerator (see FIG. 14) or is discharged into a storage ortransportation container or additional processing equipment (not shown).

The infeed and outfeed conveyors 20, 22 are substantially at groundlevel so that they may receive containerized hazardous material fromforklifts, truck beds, rail cars and the like. However, the wasteprocessing system may include multiple infeed conveyor, arranged atmultiple levels. The infeed and outfeed conveyors 20, 22 includemotorized conveyors 38, 40 adjacent to air locks 42, 44. The air locks42, 44 communicate with the elevator 24.

The construction of air locks 42, 44 is substantially identical.Accordingly, the following description will be directed to air lock 42,it being understood that the description applies as well for air lock44. Air lock 42 is totally enclosed by panels 46 which are attached to aframe 48, preferably by bolts (now shown) as shown in FIG. 2. The frame48 also encloses a motorized conveyor 50 which extends between inner andouter air lock door assemblies 52, 54, which are the specific structureof the present invention.

The following description will be directed to air lock door assembly 52,it being understood that the description applies to the construction ofair lock door assembly 54 as well as the air lock door assemblies forair lock 44 of conveyor 22. As shown in FIGS. 3, 4, and 5, the air lockdoor assembly 52 includes plate-like inner and outer panels 56, 58,separated by a rectangular spacer 60, which includes a seal (not shown),such as an O-ring seal, on each side. However, other types or seals,such as caulking seals, may be used without departing from the scope ofthe invention. The panels 56, 58 and spacer 60 are sandwiched togetherand held in position by a ring of nut and bolt assemblies 62 (see FIG.4). Inner and outer panels 56, 58 include rectangular openings 64, 66which receive seal assemblies 68, 70, respectively. Seal assemblies68,70 preferably are inflatable seals. As best shown in FIG. 5, sealassemblies 68, 70 each include a retainer frame 72 and preferably arectangular inflatable seal element 74.

As shown in FIG. 5, panels 56, 58 include pairs of vertical tracks 76,78 which receive the vertically extending ribs 80, 82 of a door 84. Thedoor 84 includes a longitudinal rack 86 which engages a pinion 88 drivenby a hydraulic motor 90. The motor 90 is mounted on panel 58 and thepinion 88 is mounted on a shaft 92 which extends through an opening 94.

As shown in FIG. 1, when a reusable canister 96 is placed upon conveyor38, the air lock door seals 74 are de-pressurized (see FIG. 5) and motor90 actuated to rotate pinion 88. This causes the rack 86 and door 84 tobe raised upwardly to open the passageway formed by openings 64, 66 toallow the motorized conveyor 38 to convey the canister 96 onto theconveyor 50 within the air lock 42.

As shown in FIG. 1, the elevator 24 is totally enclosed by panels 98which are welded to a framework 100 shown in FIG. 6. The elevator 24includes a hydraulic drive motor 102 which drives two sets of drivechains 104, 106 that are connected to a elevator platform 108 havingdriven rollers 110. The motorized rollers 110 are oriented to receive acanister 96 or other types of containerized waste from air lock 42. Thedischarger 26 is positioned at the top of the elevator 24 and intersectsa dump chamber 112 that communicates with the drop chute 28 (see FIG.1). The discharger 24 is totally enclosed by panels 114 which are weldedto a framework 116. The framework 116 encloses ram member 118,positioned adjacent to elevator 24, and ram member 120.

As shown in FIG. 7, ram member 118 includes a ram carriage 122 which issupported on four ball screw rods 124, 126, 128, 130 by ball nuts 132.Motors 134 rotate the ball screw rods to displace the carriage 122 alongthe discharger 26 (see FIG. 6). Similarly, ram member 120 includes a ramcarriage 136 which is supported on ball screw rods 138, 140, 142 by ballnuts 144. Ram member 120 is powered by a motor 146 which is connected toturn ball rod 138. Ball rods 138, 140, 142 are attached to joints 148,150, 152, respectively, so that the rods 138-142 can rotateindependently of rods 126-130, and ram member 120 is capable of movingindependently of ram member 118.

As shown in FIG. 8, ram members 118, 120 include pivoting frames 154which support gripper frames 156 for engaging canisters 96. The pivotingframes 154 each include longitudinal members 158 which areinterconnected by transverse members 160. The longitudinal members 158support slides 162 which are connected to the gripper frame 156, so thatthe gripper frame is slidable relative to the pivoting frame 154. Thegripper frame 156 includes vertical struts 164 which slidably supportsegmented sleeves 165 having segments 166, 167 which are spanned bytransverse struts 168, 169.

A bottom hook 170 is mounted on lower transverse strut 168 and hooks 172are mounted on the outside of sleeve segments 167. Sleeves 166 aresegmented so that transverse struts can be varied in vertical spacing,thereby varying the vertical spacing between hooks 172 and hook 170.Double-acting cylinder motor 174 spans the transverse struts 168, 169 ofthe pivoting frame and is actuated to move the hooks 172, 170 apart ortoward each other to grip the canister 96. Lateral cylinder motors 176are mounted on the pivoting frame 154 at one end and on the gripperframe 156 at an opposite end. Accordingly, the lateral of the cylinders176 can be actuated to displace the gripper frame 156 relative to thepivoting frame 154.

A rear panel 178 is mounted on the pivoting frame 154 and supports apivoting stud 180. Pivoting stud 180 is received within a bore 182formed within support frame cross members 184. On ram member 118 only, arotary actuator 186 is mounted which engages stud 180 and rotatespivoting frame 154. Pivoting frame 154 on ram member 120 pivots freely.Canister 96 includes bottom cut-outs 188 on opposing faces 190, 192(only cut-out on face 190 is shown) which are shaped to receive thelower hooks 170 of the pivoting frames 154.

The action of discharger 26 is shown sequentially in FIGS. 9, 10, 11,and 12. The procedure begins with the elevator platform 108 being raisedto the discharger 26. At this time, the ram members 118, 120 are in aretracted position. As shown in FIG. 10, motor 146 is actuated to driverod 138 to advance ram carriage 136 to the container 96. Cylinders 176on ram members 120 and ram member 118 are actuated to advance thegripper frames 156 toward the canister 96. When the gripper frames 156are properly positioned, the cylinders 174 (see FIG. 8) are actuated toclamp the upper and lower hooks 170, 172 together, thereby engaging thecanister 96 at both ends.

As shown in FIG. 11, the motors 134 and 146 have been actuated todisplace ram member 118 to the drop chamber 112, and similarly, motor146 has been actuated to retract ram member 120. The canister 96 is nowpositioned in the drop chamber 112. As shown in FIG. 12, the rotaryactuator 186 is activated to rotate pivoting frame 154 to rotatecanister 96 to a dump position. Pivoting frame 154 of ram member 120,which pivots freely, is also rotated. The rotary actuator is adjusted torotate the canister 96 through 180° so that all of the contents aredumped in the drop zone. Once the dumping action has been completed, therotary actuator 186 rotates the gripper frames 154 to an uprightposition, as shown in FIG. 11, and the two ram members 118, 120 aredisplaced sidewardly to the configuration shown in FIG. 10. Thecylinders 174 are actuated to disengage the upper and lower hooks 172,170 from the canister 96, and the cylinders 176 actuated to displace thegripper frames 156 from the canister 96. At this time, the canister 96is resting upon the elevator platform 108 (see FIG. 9).

The ram member 120 is displaced sidewardly away from the canister 96 tothe position shown in FIG. 9, and the elevator 24 (see FIG. 6) actuatedto lower the canister 96 to where it is level with air locks 42, 44. Theair lock door 54 is opened and the conveyor 110 actuated to displace theempty canister to within the outfeed air lock 44, where it is receivedby powered rollers 50. The outfeed air lock door 54 closes, the outfeedair lock 42 is purged and door 52 opens to allow the canister 96 to bedisplaced sidewardly to outlet conveyor 40.

As shown in FIG. 13, if disposable containers, such as 55 gallon drums190 supported by a pallet 192 are to be disposed of, ram member 120 isnot actuated. Rather, ram member 118 is actuated to displace the pallet192 and container 190 sidewardly to the drop zone 112. For this type ofwaste, the gripper frame 156 of the ram member 118 is not displacedforwardly since the hooks are not used to engage the container.

As shown in FIG. 14, the drop zone 112 is enclosed within a drop chute28 having explosion doors 129. Drop chute 28 which feeds a dual auger 30having a pair of opposing, tapered auger screws 194. The dual auger 30also includes a pair of doors 196 which control the residence time ofwaste material within the dual auger compartment.

The single auger 32 includes a single auger screw 198 which receivesshredder material from the dual auger 30 and further reduces andcompresses it, and pumps it through an outlet, extrusion tube 200. Theextrusion tube 200 is connected to a an injector auger 34 which pumpsthe material into a rotary reactor 202. Injector auger 34 also couldpump material into a container or additional processing or conveyingequipment (not shown), such as a ball mill. As shown in FIGS. 1 and 14,a rotary gate 204 is positioned between the injector 34 and reactor 202,and can be opened and closed to prevent burn-back or escape of material.The dual auger 30 preferably has the construction of the dual augerdisclosed in Koenig U.S. Pat. No. 4,938,426. The single auger 32preferably has the construction shown in Koenig U.S. Pat. No. 4,951,884,and the injector mechanism preferably has the structure shown in KoenigU.S. Pat. No. 4,915,308, the disclosures of these patents beingincorporated herein by reference. Further, the rotary door structure isdisclosed in Koenig U.S. Pat. No. 5,088,422, filed Dec. 21, 1990, thedisclosure of which is incorporated herein by reference.

As shown in FIGS. 15, 16, and 17, the slide box 36 includes a housing206 having a front wall 208, a rear wall 210 and transverse supportmembers 212, 214, 216, 218. A flange 220 is mounted on front wall 208and is connected to the injector auger 34 (see FIGS. 1 and 14). Rearwall 210 includes outlet flange 222 which is connected to a feed conduit224 (see FIG. 1) that is connected to the reactor 202.

A forward frame 224 is mounted against the front wall 208 and a rearwardframe 226 is mounted against the rear wall 210. The forward frame 224forms a space 228 which receives a forward slide plate 230 Similarly,rear frame 226 forms a space 232 with rear wall 210 and receives rearslide plate 234. A through conduit 236 extends between forward andrearward slide plates 230, 234, and a diverter conduit 238 extendsbetween forward and rearward slide plates 230, 234. The slide plates230, 234 are positionable within slots 228, 232 such that alternately,conduit segment 236 or conduit segment 238 are in registry with flange220.

Forward and rearward slide plates 230, 234 include upwardly extendingbosses 240, 242 which are attached to double-acting cylinder motors 244,246 that are anchored on angle stops 248, 250 mounted on longitudinalangles 214. Accordingly, the cylinder motors 244, 246 are selectivelypositionable to displace the forward and rearward slide plates 230, 234,thereby positioning the conduit segments 236, 238 in registry withflange 220, and in the case of conduit segment 236, in registry withflange 222.

As shown best in FIG. 17, conduit segment 238 includes a substantiallyrectangular bottom opening 252 and a diverter plate 254 which acts todeflect incoming material downwardly through the bottom opening 252.

As shown best in FIG. 16, inlet and outlet flanges 220, 222 includeannular gaskets 256, 258. Conduit segment 236 includes front and reargasket elements 260, 262 which form an air-tight seal with gaskets 256,258, respectively, when the conduit segment 236 is in registry withflanges 220, 222. Similarly, segment 238 includes gasket 264 which formsan air-tight seal with gasket 256 when these front and rear slide plates230, 234 are displaced to place conduit segment 238 in registry withflange 220.

All of the hydraulic motors and hydraulic cylinder motors of the wasteprocessing system shown in FIGS. 1-17 are controlled by a singleprogrammable logic controller. As shown in FIG. 18, programmable logiccontroller 256 receives a signal from pressure sensor 258 when canister96 is placed upon motorized conveyor 38. Valve 260 is actuated toactivate the outer door motor 90 to raise the outer door 84 of air lockdoor assembly 52 of air lock 42. Valve 262 is actuated to activate theinfeed conveyor 38 to displace the canister 96 through the opening inthe air lock door 52 into the air lock 42. Simultaneously, the valve 264is actuated by controller 256 to energize the conveyor 50 to receive thecontainer 96 and displace it to the interior of the air lock 42. Valve260 is again actuated to lower the door of the outer air lock assembly52, and valve 266 actuated to pressurize the seals to secure the outerdoor assembly 52. A photoeye 268 senses the presence of the canister 96within the air lock 42 and the controller 256 actuates the valves 266,264 to stop the conveyors 38, 50. Proximity switches 270 located onouter door assembly 52 determine the displacement range for the door 84within the outer air lock door 52. Alternately, a resolver may be usedto determine the position of the door.

At this time, valve 272 is actuated to depressurize the seals of theinner air lock door 54. Proximity switch 274 indicates that the elevatorplatform 108 is in the down position so that the platform is level withthe conveyor 50. A photo-eye 276 within the elevator shaft senses thatthe elevator platform 108 is empty, and valves 264 and 278 are actuatedto displace the canister 96 from the air lock 42 onto the elevatorplatform 108. Valve 280 is actuated to lower the inner air lock door 54and valve 272 actuated to pressurize the seals on that door. Valve 282is actuated to energize the motor 102 of the elevator to raise theplatform 108 to the discharger 26.

A proximity switch 284 is tripped when the elevator platform 108 reachesthe discharger 26 and the controller 256 actuates motor valve 282 tostop the elevator. A photoeye 286 in the discharger detects the presenceof a canister (as opposed to waste material contained in disposablecontainers such as drums), and the ram members 118, 120 are actuated ina sequence described with reference to FIG. 19. When the empty canister96 is returned to the elevator platform 108 and is lowered to groundlevel, proximity switch 274 indicates that platform 108 is at the properlevel. Valve 272 is actuated to depressurize the seals on door 54 andvalve 280 actuated to raise the door. Valves 262, 264 are actuated todisplace the container 96 sidewardly into the outfeed air lock 44, anddoor 54 is shut and sealed.

Valve 288 is actuated to purge the volume within air lock 42 with gas sothat the contaminated air is driven into a charcoal canister oralternately, to the reactor 202. When the purge has been completed,valve 266 is actuated to de-pressurize seals on door 52 and valve 260actuated to open the outer door. Valves 266 and 264 are actuated todisplace the container 96 outwardly to be collected.

The arrangement of valves and sensors for air lock 44 is the same as forair lock 42. Specifically, controller 256 actuates valves which controlthe pressurization of seals for doors 52, 54 of air lock 44 and for themotorized conveyors 40 and 50 of air lock 44.

Valve 294 actuates the cylinders 176 on pivoting frame 154 of ram member118 to displace the hooks 172, 170 forwardly, and valve 296 is actuatedto clamp the hooks together to engage the canister 96.

Valve 298 actuates motor 146 to displace the ram member 120 sidewardlyuntil proximity switch 300 is tripped, indicating that the ram member120 is snug against the container 96. Valve 302 is actuated to energizecylinder motors 176 on pivoting frame 156 of ram member 120 to advancethe hooks 170, 172 forwardly. Valve 304 is actuated to activate cylinder174 to clamp the hooks 170, 172 against the container.

Valves 290 and 298 are again actuated to activate motors 134, 146 todisplace the container 96 sidewardly to the drop zone 112. Proximityswitch 306 is tripped when the container is properly positioned. Valve308 is actuated to activate the rotary actuator 186 to rotate thepivoting frame 154 of ram member 118, and consequently, pivoting frame154 of ram member 120, to dump the container 96. Proximity switch 310 istripped when the container has been inverted 180 degrees.

The controller 256 then actuates valve 308 to rotate the container 96back to an upright position and the valves 290, 298 actuated to displacethe container 96 sidewardly to the position shown in FIG. 6. A proximityswitch 312 indicates when the ram members 118, 120 are properlypositioned. Valves 302, 304 are actuated to reposition the fingers 170,172 away from engagement with container 96, and valve 298 actuated toactivate motor 146 to displace ram member 120 sidewardly to the positionshown in FIG. 6. A proximity switch 314 is tripped when the ram member120 is properly positioned.

In addition to the foregoing sensors and valves, the programmable logiccontroller system also includes an oxygen sensor 316 and preferablyincludes a pressure sensor 318 to detect a predetermined gas pressurewithin the system of the present invention so that it may be maintainedat a predetermined value. Valves 320, 322 are actuated to release aninert gas, such as nitrogen, or to depressurize the system. Further amercury sensor 324 preferably is placed in the dual auger shredder 30,and the presence of mercury causes controller 256 to actuate valve 326to activate cylinder motors 244, 246 of slide box 36 to position conduitsegment 238 in line with flange 220 (FIG. 15) to divertmercury-contaminated waste from reactor 202. However, such sensors arewell-known in the art and therefore are not illustrated here.

The waste processing system may be adapted to suit a particularconfiguration of incinerator or other waste handling device.Accordingly, other geometries comprising the infeed conveyor, elevator,discharger, drop, and augers may be employed.

For example, as shown in FIG. 20, the system of the present invention isutilized in combination with a kiln 202 having an infeed chute 330 whichis at an elevation above that of the infeed conveyor 20. Consequently,the single auger 32 is elevated from the ground and supported on a frame332 so that the injector auger 34 and feed tube 224 are elevated to feedinto the infeed chute 330. Also, the entire waste processing system maybe offset from the face 334 of the rotary reactor 202 in order to allowclearance for other feeding equipment and fuel input.

As shown in FIG. 21, the waste processing system may be utilized incombination with a sag mill, generally designated 336. In thisembodiment, the single auger 32 discharges material through theextrusion tube 200 into a modified injector auger 34'. Injector auger34' includes a feed tube 224' which is inclined upwardly to the infeedplenum 338 of the sag mill. Consequently, although the single auger 32is at the same level as the inlet to the elevator 24, the system mayfeed a device whose inlet is substantially above ground level.

As shown in FIG. 22, the waste processing system of the presentinvention may be utilized with a rotary kiln 202 having a face 344 whichis connected to the feed tube 224 of the injector auger 34. The injector34 and feed tube 224 is substantially horizontal with respect to therotary kiln 202, and is at a higher elevation than the infeed andoutfeed conveyors 20, 22 respectively.

As shown in FIG. 23, the waste processing system of the presentinvention may utilize a second infeed conveyor 20', having a secondinfeed airlock 42' with inner and outer doors 52', 54', respectively,which is connected to elevator 24'. Second infeed conveyor 20' islocated at an elevation above that of infeed conveyor 20, preferably ona floor above the floor supporting conveyor 20 (which may be at groundlevel or below). Second infeed conveyor 20' includes a motorizedconveyor 38' for supplying containerized or palletized material to theconveyor, which conveys the material to elevator platform 108 (see FIG.6). Consequently, the system of FIG. 23 can receive material frommultiple locations at multiple elevations.

While the form of apparatus herein described constitutes a preferredembodiment of this invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention.

What is claimed is:
 1. A door assembly for providing a sealedenvironment in an air lock of a waste processing system, said doorassembly comprising:a vertical sliding door member; and a selectivelyinflatable gasket assembly located along a perimeter of opposing facesof said door member, whereby a perimeter of said door assembly isentirely supported and sealed on said opposing faces by said gasketassembly when said door member is in a closed position.
 2. A doorassembly for providing a sealed environment in an air lock of a wasteprocessing system, said door assembly comprising:a sliding door member;a selectively inflatable gasket assembly located along a perimeter ofsaid door member, whereby a perimeter of said door assembly is entirelysupported and sealed when said sliding door member is in a closedposition; a pair of plate-like inner and outer panels; and a rectangularspacer gasket positioned to separate said inner and outer panels,whereby said panels are spaced to support said door member.
 3. The doorassembly of claim 2 wherein said inner and outer panels and said spacergasket are positioned and held together by a ring of bolt and nutassemblies.
 4. The door assembly of claim 3 wherein said inner and outerpanels each contains a rectangular opening having a perimeter forreceiving said inflatable gasket assembly.
 5. The door assembly of claim4 wherein said inflatable gasket assembly comprises a retainer frame anda rectangular inflatable seal element.
 6. The door assembly of claim 5wherein said inner and outer panels contain a pair of vertical tracksfor receiving vertically extending ribs located on said sliding doormember.
 7. The door assembly of claim 6 wherein said sliding door memberincludes a longitudinal rack which engages a pinion mounted on a shaftextending through an opening in said outer panel.
 8. The door assemblyof claim 7 wherein said pinion is driven by a hydraulic motor mounted onsaid outer panel.
 9. The door assembly of claim 1 wherein there are twodoor assemblies for said air lock.
 10. The door assembly of claim 9wherein the door assemblies are located on opposite sides of said airlock.
 11. A passageway for an air lock of a waste processing systemcomprising an entrance and an exit for ingress and egress from said airlock; said entrance and exit including a first panel having a firstopening therethrough, a second panel having a second opening in registrywith said first opening, a spacer gasket separating said first andsecond panels and forming an interior volume, a door slidably mountedwithin said interior volume for opening and closing said passageway,means for displacing said door within said volume, and means forselectively forming a seal between said panels and said door.
 12. Thepassageway of claim 11 wherein said seal means includes a firstselectively inflatable seal member and a first seal retainer frameextending about a periphery of said first opening, whereby a seal isformed between said first panel and said door when said first sealmember is pressurized.
 13. The passageway of claim 12 wherein said sealmeans includes a second selectively inflatable seal member and a secondseal retainer frame extending about a periphery of said second opening,whereby a seal is formed between said second panel and said door whensaid second seal member is pressurized.
 14. The passageway of claim 11wherein said displacing means includes a longitudinal rack mountedwithin said volume on said door which engages a pinion mounted on ashaft extending through an opening in said first panel, and wherein saidpinion is driven by a hydraulic motor mounted on said first panel.
 15. Adoor assembly for an air lock of a waste processing system comprising:avertical sliding door member; said sliding door member having aperimeter entirely supported when said sliding door member is in aclosed position and sealed by a selectively inflatable gasket assemblylocated along said perimeter; inner and outer panels separated by arectangular spacer gasket for supporting said sliding door member; saidinner and outer panels each containing a rectangular opening having aperimeter for receiving said inflatable gasket assembly; said inflatablegasket assembly including a retainer frame and a rectangular inflatableseal element; a pair of vertical tracks located between said inner andouter panels for receiving vertically extending ribs from said slidingdoor member; a longitudinal rack located on said sliding door memberwhich engages a pinion mounted on a shaft extending through an openingin said outer panel; and a hydraulic motor mounted on said outer panelfor driving said pinion.
 16. The door assembly of claim 15 wherein thereare two door assemblies for said air lock.
 17. The door assembly ofclaim 16 wherein the door assemblies are mounted on opposite sides ofsaid air lock and communicate with an elevator means and a conveyormeans.